This invention relates to an automatic whole blood collection system. It relates more particularly to a method and apparatus for standardizing volumetric whole blood collection and red blood cell mass collection so that the collection process can be accomplished efficiently with minimum damage to the blood and with minimum discomfort to the donor.
Prior systems for collecting blood rely on venous pressure and hydrostatic pressure to cause blood to flow from a donor""s arm. A phlebotomy needle that is connected by tubing to a blood collection bag containing anticoagulant is inserted into a donor""s arm. Hydrostatic pressure is achieved by positioning the collection bag about 18 inches below the level of the donor""s arm and venous pressure is controllable to some extent by varying the pressure in a cuff attached to the donor""s arm above the venipuncture site and, by directing the donor to alternately flex and relax his/her hand. Older collection apparatus used a relatively large needle (e.g., 16 gauge) which, when inserted, caused appreciable patient discomfort. Also, during the collection process, the non-anticoagulated whole blood drawn from the donor had to pass through the phlebotomy needle and along a length of tubing before it reached the anticoagulant in the blood collection bag. If the rate of flow of blood through the tubing was not maintained high enough, clotting could occur, reducing the usefulness of the collected blood.
To avoid the aforementioned problems, there has been developed relatively recently blood donation apparatus which utilizes a peristaltic or roller pump to withdraw whole blood from a donor through a much smaller (e.g., 19 gauge) phlebotomy needle, and to pump the blood through a tube leading to the collection bag. Anticoagulant flowing through a second tube leading from an anticoagulant source is mixed with the whole blood right at the outlet of the phlebotomy needle. The anticoagulant tube passes through the same pump head that draws the whole blood from the donor, so that the ratio of blood to anticoagulant is determined by the ratio of the diameter and elastic properties of the drawn blood tube with respect to those of the anticoagulant tube. Such a blood donation apparatus is disclosed in U.S. Pat. No. 4,385,630.
While that patented apparatus is a considerable improvement over the prior blood collection apparatus, it still has certain drawbacks. For example, it must be primed manually so that anticoagulant fills the anticoagulant tube down to the phlebotomy needle. Also, it employs a peristaltic pump with a single roller pump head acting on both the blood tube and anticoagulant tube. Therefore, the blood-to-anticoagulant ratio depends upon the tubing characteristics, making it difficult to change that ratio. Still further, the disposable blood collection set used in that prior blood donation apparatus is relatively difficult to install in the pump unit such that the drawn blood and anticoagulant tubes are properly positioned on the unit""s pump head.
That patented blood donation apparatus is further disadvantaged because it is only able to collect a set volume of whole blood. Often, it is desirable to have the option of collecting different blood volumes. For example, in some cases, it may be necessary to collect a specific mass of red blood cells (RBC) based on the donor""s known hematocrit, i.e., the percentage by volume of RBC in drawn whole blood. Even if the target volume of RBC is always the same in such cases, the volume of whole blood to be drawn will vary from donor to donor.
Finally, that known apparatus does not provide a record of the collection procedure and does not positively correlate the drawn blood with the donor of that blood. Therefore, there is always the possibility of the collected blood being misidentified and misused.
Accordingly, it is an object of the present invention to provide a fully automatic whole blood collection system.
Another object of the invention is to provide a collection system of this type which is self-priming.
A further object of the invention is to provide a system such this which is relatively easy to use.
Yet another object of the invention is to provide such a system which is programmable to allow the collection of different blood volumes.
Still another object of the invention is to provide a whole blood collection system which facilitates positive identification of the donor""s blood and simplifies the keeping of records relating to the blood donations.
A further object of the invention is to provide a blood collection system which allows phlebotomists to draw blood safely and reliably from several donors in rapid succession.
Yet another object of the invention is to provide a disposable blood collection set for use in the above system.
A further object of the invention is to provide a method of tracking a donor""s blood collected by the above whole blood collection system.
Other objects will, in part, be obvious and will, in part, appear hereinafter.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying the features of construction, combination of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.
Briefly, the whole blood collection system of the present invention comprises an automated pump/control unit and an accompanying disposable blood set. When combined and connected to a source of anticoagulant, these elements allow automatic priming of the blood set with anticoagulant and automatic collection of anticoagulated blood product according to three different collection modes to be described. As will be seen, the unit""s pump and the blood set are specially designed to cooperate during the collection process to assure that the collected product has a precise blood to anticoagulant ratio, typically in excess of 5:1, e.g., 8:1.
During the collection procedure, the pump/control unit automatically collects data relating to the procedure. Additional data specifically identifying components of the blood set, such as the blood collection bag, along with identification data on the donor""s registration form and on various blood samples may be scanned into the pump/controller unit by a scanner associated with the unit; this facilitates positive sample identification and tracking. At the end of the procedure, a printer in the pump/controller unit automatically prints out this information so that a detailed record is immediately available about the collected blood product, the procedure for collecting it and the source of the product, i.e., the donor. Thus, there is minimum likelihood of the product being mislabeled.
As will be seen, the system is easy to use and quite efficient so that the collection time is kept to a minimum, allowing a phlebotomist to draw blood safely and reliably from several donors in rapid succession with minimum discomfort to the donors.